In an example of an image forming apparatus such as a laser printer, a cleaning roller for removing extraneous matter such as residual toner and paper debris on the peripheral surface of a photosensitive drum is provided. The cleaning roller is disposed so that the peripheral surface thereof is in contact with the peripheral surface of the photosensitive drum. The cleaning roller rotates so that the part thereof in contact with the peripheral surface of the photosensitive drum moves in the same direction as the moving direction of the peripheral surface of the photosensitive drum.
The driving force for rotating the cleaning roller is transmitted from the photosensitive drum. That is, at one end of the photosensitive drum, a drum gear that rotates integrally with the photosensitive drum is provided. On the other hand, at one end of the cleaning roller, a cleaning gear that rotates integrally with the cleaning roller is provided. The cleaning gear meshes with the drum gear. When driving force is input into the photosensitive drum, the photosensitive drum rotates, the driving force is transmitted from the drum gear to the cleaning gear, and the cleaning roller rotates.
However, since the drum gear and the cleaning gear are meshing with each other, the meshing state thereof may cause unevenness of the rotation speed of the drum gear (the photosensitive drum) and may cause banding (stripes appearing in an image due to uneven density).